In a typical on-shore wind turbine installation, various components of the wind turbine, such as, for example, the nacelle, tower or tower sections, rotor hub, rotor blades, etc., may be transported to the installation site separately and then assembled together on site so as to result in an operational wind turbine. In this regard, due to the relatively large size of some of these components, the transportation thereof is typically carried out using one or more tractor trailers, which travel along the existing network of roads, highways, expressways, etc. (collectively referred to herein as roads) to the installation site. Additionally, in off-shore wind turbine installations, which can be significantly larger than on-shore installations, wind turbine components are typically transported using tractor trailers on the existing network of roads from a factory, for example, to quayside where the components may be loaded onto boats for transport to the off-shore installation site.
Many of the existing roads used in the transportation of wind turbine components are divided into lanes so as to accommodate other vehicles moving in, for example, the same direction or an opposing direction, and may further have a shoulder on the sides of the outer most lanes. These lanes have a certain width that, in the normal course, accommodates most of the traffic on the road. Moreover, in many countries, regions, etc., various road signage is located just off the shoulders for aiding, informing, guiding, etc. those traveling on the road. In many instances, the distance between the inner boundary of the outer lane and the road signage may be between 5 to 6 meters. This distance then represents the maximum width of a vehicle (or a load carried by the vehicle) that may travel on the road without obstructing vehicles traveling in an adjacent lane and without damaging or otherwise destroying the road signage adjacent the road.
Additionally, many existing roads pass under bridges at highway intersections and similar junctions. In some circumstances, these bridges only provide a height clearance of 4 to 5 meters from the surface of the road. This height clearance represents the maximum height of a vehicle and its associated load that may travel on the road without impacting the bridge. Most existing roads do not extend in a completely straight path, and the transport path from the factory to the installation site or quayside may include a number of curves and turns at road intersections. Therefore, a vehicle transporting a wind turbine component must also traverse curved paths in the road as well as relatively sharp corners at road intersections, in addition to staying within the maximum width during normal operation and staying within the maximum height when going under a bridge.
Wind turbine blades are typically transported to an installation site or quayside on a tractor trailer. Conventionally, the blade was typically loaded on a tractor trailer and secured thereto in a fixed position so that the blade did not essentially move during transit. However, the trend in wind turbine construction has been for the power output and physical size of the wind turbine to scale upward. As a result, more recent wind turbine blades have included larger lengths and widths that increase the difficulties of transporting the blades on existing roads. Transportation devices have been developed for transporting these larger wind turbine blades.
For example, the transportation device described in U.S. Pat. No. 7,303,365 to Wobben operates to rotate the wind turbine blade along its straight longitudinal axis during transport so that a maximum width of the blade is oriented generally horizontal to fit under bridges and oriented generally vertical to limit the total width of the vehicle and load during normal operation. However, this transportation device continues to struggle with managing the length of the blade during sharp turning or cornering operations.
Also US 2011/0142589 discloses a way of dealing with passing low passages, however in relation to transporting curved blades. A curved blade is held in a pivotable and slidable cradle (FIG. 2, reference 140). While passing low passages the curved blade is tilted to pass a first section of the passage by keeping a root end (56) of the blade low, while the tip end (54) is high, and passing the remaining part of the passage by elevating the root end (56) of the blade, which lowers the tip end (54) of the blade (FIG. 3). Again, this document only relate to passing low passages and not turning in any way.